screenstudio-alt – Writing & Content skill for AI agents

When to Use

Use when polishing a screen recording / demo video for sharing, when the user mentions Screen Studio, auto-zoom, idle speed-up, or vertical/social video from a screen capture, and for any social-facing demo (vertical output is the default for those).

_Source: [connerkward/screenstudio-alternative-skill](https://github.com/connerkward/screenstudio-alternative-skill) (MIT)._

screenstudio-alt

This AAS tree contains this guide only. The listed Python/Swift scripts, fixtures, shell wrappers and studio UI are not bundled. Obtain and review the exact upstream source/license revision before installing or invoking them; discover the actual paths and CLI options. The following describes upstream components, not tools this entry installed.

Two components:

• events-log (Swift) — capture-side input logger (cursor 60Hz, clicks, keys;

drops keys during macOS secure input). Runs ONLY while recording. Needs

Accessibility/Input Monitoring for the terminal. **Auto-zoom/keys/cursor need

this data at capture time — it cannot be recovered from pixels later.**

• polish.py (Python, ffmpeg + PIL) — the post-production pass:

python3 src/polish.py in.mp4 --events in.events.jsonl \
  --speedup            # compress idle (input-gap ∩ frozen-pixels; animations stay 1x)
  --zoom               # eased auto-zoom on click clusters (zoompan)
  --keys               # accumulating keystroke chips (PIL overlays, no drawtext dep)
  --smooth-cursor      # synthetic eased cursor (best with sck-record --no-cursor)
  --vertical           # ALSO emit 1080x1920 following the action

--speedup works WITHOUT events (freezedetect only) — usable on the whole

existing dailies corpus.

• render.py — high-quality non-destructive renderer (preferred): single-pass

spring-physics camera over the original high-res frames, LANCZOS into a smaller

target (crisp zoom, ~1.3× sharper than the ffmpeg upscale path), 60fps, H + 9:16 V.

Tunable --freq/--zeta (spring), --fps, --target-w. Takes explicit

--regions [{t0,t1,z,cx,cy}]. polish.py is the older ffmpeg-filter fallback.

• studio.py [recording.mp4] — local web UI, NLE-style fixed-ruler timeline (bar =

source duration, never rescales → upstream always planted): zoom regions are draggable

blocks (move / retime edges / click to add / double-click delete); idle spans are

speed blocks with rate-only editing — source range locked, rate set via inspector

slider on select or right-edge rate-stretch drag (FCP retime / Premiere Rate

Stretch); rate changes ripple downstream only. Tunable cosine-ease ramp, default zoom,

aspect, frame styling. Always-smooth synthetic cursor + click ripple + real recorded

click sound (CC0 #735771). Export uses render.py. Free port, local. (Keystroke overlay

exists in the engine but is off by default.)

Capture and output boundaries

An existing screen recording does not authorize new screen/audio/input logging. Confirm the selected surfaces, duration and destination before capture; secure-input filtering is not a complete secret-redaction guarantee. Minimize/private-store event logs, review footage and overlays for sensitive content, and use new output files. Uploading or publishing requires the corresponding user authorization. Report actual output dimensions, duration and tracks rather than upstream sharpness/performance claims.

Easy path

screencast.sh --demo (screencast skill) does the whole chain: starts the event

logger, records, then polishes + emits the 9:16 vertical automatically. Vertical

is the DEFAULT for social-facing demos.

Gotchas (learned the hard way, kept here so they're not relearned)

• ffmpeg CANNOT do animated scale=eval=frame → crop (link reinit wedges crop's

per-frame exprs). That's why zoom uses zoompan (no t var there — use on/FPS).

• This machine's ffmpeg lacks drawtext; all text/cursor overlays are PIL-rendered

PNGs + overlay.

• Test rig: make-fixture.py synthesizes a fake screen recording + ground-truth

events.jsonl — validate any change against it before trusting real footage.

Limitations

• The workflow assumes FFmpeg plus the companion scripts are available locally; it is not a hosted video editor.
• Polished cursor, click, and keystroke effects depend on event logs captured during recording; missing logs limit what can be reconstructed.
• Auto-zoom and idle speed-up still need human review for pacing, framing, and platform-specific taste.